Final Results

Finding Cool & Warm Colors

Step 1

Open a photo you would like to edit. Or, you may use the photo used in this tutorial (from iStockPhoto).

Step 2

The Lab color mode contains a chroma A channel that identifies the cool and warm colors. To access this channel, change the color mode to Lab color (Image> Mode> Lab Color)

Step 3

Now that we're editing in Lab color, we can grab the channel. But before we do this, we need to create a new layer (Layer> New> Layer or Shift+Ctrl+N) .

Step 4

After creating a new layer, we'll add the chroma A channel to the layer. With the new layer selected, use the Apply Image tool (Image> Apply Image) to set the following properties:
Layer: Merged
Channel: a
Invert: Unchecked
Blending: Normal
Opacity: 100%

Blending and Tweaking

Now that we have our layer with the cool and dark colors defined, we can blend the layer into the image and adjust the results.

Step 5

To blend the layer into the image, simply change the blending mode of the top layer to Soft Light.

Step 6

We'll be using the Levels tool to adjust the effect. Open the Levels tool (Image> Adjustments> Levels or Ctrl+L). To increase the effect, move the black and white input sliders towards the center.